1. Field of the Invention
The present invention relates to a vehicle including an engine and a shutter device configured to adjust a temperature of coolant water of an engine by adjusting an amount of outside air introduced into a radiator.
2. Description of the Background Art
Japanese Patent Laying-Open No. 2011-105219 discloses a vehicle including a shutter (grille shutter) capable of switching between an opened position of introducing outside air into a radiator and a closed position of prohibiting or suppressing introduction of the outside air. This vehicle further includes a motor configured to drive the shutter and a control device configured to control opening/closing operation of the shutter by applying a current to the motor. The control device performs an abnormality determination as to an operating state of the shutter based on a current value provided at the time of intermittently applying a current to the motor (refer to Japanese Patent Laying-Open No. 2011-105219).
Various controls are performed based on a temperature of coolant water of an engine. For example, a temperature of coolant water of an engine may be used for a failure diagnosis for a thermostat valve provided on a passage through which engine coolant water flows, an oil temperature estimation for the engine, or the like.
Opened and closed states of the shutter (grille shutter) disclosed in Japanese Patent Laying-Open No. 2011-105219 described above affects a temperature of coolant water of the engine. When this shutter is rendered to be immovable in the opened state due to a failure or jamming of a foreign object, a gap between a drop in a coolant water temperature during stopping of the engine and a rise in a coolant water temperature at the time of operation of the engine increases, causes a change in the coolant water temperature to increase. This tendency is particularly remarkable in a hybrid vehicle in which an intermittent operation (stopping/operating) of an engine is performed in accordance with an SOC (State Of Charge) of a power storage device, traveling power, or the like.
An excessive change in the engine coolant water temperature may cause an incorrect operation in various controls executed based on the coolant water temperature. Such a problem has not been particularly reviewed in the patent document described above.